Device for locating the position of a movable body



une-99 i936, H. E. sJsTRAND v 2,043,336

DEVICE FOR LOCATING THE POISITION'OF A MOVABLE BODY Filed Dec. l, .932 ssheets-sheet 1.

June 9, 1936- r H. E. sJos-rRAND f 2,043,336

DEVICE FOR LOCATING THE POSITION OF A MOVABLE BODY Filed Deo. 10, 1932 3Sheets-Sheet 2 Ilm/ENTER E. EJDETRAND,

HIE TTDENr-:ya

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H. E. SJSTRAND DEVICE FOR'LOCATING THE POSITION OF A MOVABLE BODY FiledDec.' 1o, 1952 s sh'eets-shegt s INVENTDR' .EJEJETFLAN'D HE AT TURNEYE.

Patented June 9, 1936 PATENT OFFICE DEVICE Eon LooATnvG 'mE POSITION OF.A MOvABLE Boor Hjalmar E. Sjstrand, Kavala, Grangesberg,.

Sweden Applicaties December 1o, 1932, serien No. 646,7. .9 iaolaims.(o1. 25o-ii) My invention more particularly relates to ay device whichutilizes electromagnetic Waves transmitted from spaced stations of knownpositions for geographically locating the position 5 of a movable bodywith respect to the surface of the earth. My invention is particularlyapplicable for use in locating theposition of a vessel or airplane withreference to the surface of the earth, although it will be understoodthat it is equally applicable for indicating the position of any movablebody.

In my pending application Ser. No. 646,728 I have shown and described adevice for indicating the position of a movable body in which a charton'which the indication is made is continuously maintained in anoriented'position.

One of the objects of my invention is the provision of means forindicating on a chart which is mounted on a movable body and which isxed with respect thereto, the position of the movable body.

In the embodiment of my invention illustrated,

electromagnetic waves of diierent characteris-l tics are transmittedfrom spaced stations of known positions, and means are provided forutilizing the waves and indicating on the chart the position of themovable body.

In accordance with my invention the means for indicating the position ofa movable body `on the chart preferably comprises a rotatable oroscillatable antenna wire loop with associated means for producingvisible lines passing through points on the chart which correspond tothe positions of the transmitting stations coinciding in direction withthe direction lines ffrom the movable body to the transmitting stations.

Other objects of my invention will appear in the s pecication and willbe. more particularly pointed out in the claims. My invention will bestbe understood by reference'to the accompanying drawings in which.

I have illustrated a preferred embodiment thereof and in which- Fig. 1is a diagrammatic perspective view of a device embodying my invention;

Fig. 2 is a plan view partially broken away illustrating one of -thedevices that is positioned over the point on the chart corresponding tothe 5o position of a given transmitting station;

Fig. 3 is a section taken along the 1ine'3-3 of Fig. 2: Y

Fig. 4 is a perspective view'illustr'ating 'av supporting bracket forcertain of the parts illus- 65 trated in 2 and'3;

Fig. v5 is a fragmentary plan view of certain of the parts;

Fig. 6 is a side view o f Fig. 5;

Fig is an enlarged sectional view through the portion of the indicatingdevice carrying one of the pointer arms;

Fig. 8 is a sectional viewrtaken along the linel 8 8 of Fig. '7;

Fig. 9 is a sectional view through a portion of the device which Orientsa rotatable member;

Fig. 10 is a plan view of Fig. 9; Fig. 11 is a sectional plan View takenalong the line II-II of Fig. 9; Fig. 12 is a diagram of connections forthe device which orients said rotatable member; p

Fig. 13 is a sectional View of a modication which maybev substituted forthe device illustrated in Figs. 2 and 3;

Fig. 14 is a plan view of Fig. 13; Fig. 15 illustrates diagrammaticallya modied form oi relay, and

.is mounted on a suitable frame Il which is in turn mbunted on a shaftI2 having its bearings in' standards I3 and I3a which are xed on thevessel or other movable body. The shaft I2 is preferably continuouslyrotated during the operation of the device, in the embodimentillustrated, by a, sprocket I4 secured'on the shaft I2 and which isrotated by a sprocket chain I5 which may be connected to any suitablesource of power.

- The lower end ofthe shaft I2 is received an opening in the upper endof a hub I6 and a bevel gear Il is secured on the shaft adjacent thehub. A second bevel gear I8, preferably having the same numberof teethas the bevel gear I1, is mounted yon a shaft I 9 the upper end of whichis received in an Opening in the lower end of the Ihub Ip. The hub I6passes thmugh an opening 20 in a gear whee12l, the purpose of whichvwill be more fully hereinafter described. A planetary e gear 22 engagesthe bevel gears I1. and Il and is mounted on .a shaft 23 which is, inturn, mounted in the gear wheel 2l.

're the lower ena er nie shaft Isis secured a i bevel gear 2l engagingthe gear teeth on one side of a double bevel gear 25 mounted on a shaft26 having its bearings in parts which are fixed i to the movable bodyand one of which is indicatwhich it may be clamped by a, Wing nut 43.

` as by rivets 32c.l The shield is preferably secured ed at 21. Thedouble bevel gear 25 is preferably of the same size and has .on eachsidethe same number of teeth as the bevel gear 24.'

T'he teeth on the one side of the double bevel gear 25 are engaged'by abevel gear. 28, prefer-l ablyhaving the same number ,of teeth as does fthe bevel gear 24 and mounted on an arm 29 pivoted on the shaft 26.Sleeves 30 are secured to the bevel gears 28 and L28|'and form part oftelea flange 36 which may be secured to one side of the casing, as bestshown in Figs. 2 and 3.

' The casing 32r is preferably mounted on'an arm 38 (Fig. 1) the end ofwhich is pivoted to aniarm 39 and capable of being clamped thereto by awing nut 40. mounted on a stud l4| on a. fixed support 42 to The arms 38and 39 permit the positioning of the casing 32 over any desired point ona chart 44 mounted on a frame or panel 45 which is xed to the vessel orother movable'body. In the embodiment illustrated, .the frame 45 ismounted in a vertical position, although it will be understood rthat thesame maybe mounted in a horif 'zontal or other desired position.

Mounted on the end of the shaft 3| betwee the portions 31a and 31h ofthe offset portion 31 of the rbracket is a bevel gear 46 secured to andpreferably integral with a hub 41 which may be secured to the shaft 3|asby'a pin y48. The bevel gear 46 meshes with a bevel gear 49, pref'-erably having the same number of teeth as the bevel gear 46 andpreferably integral with a cylindrical member 50 mounted on a shaft 5|,the upper end of which is received in a socket 52 in the bracket'member35 and is secured thereto as by apin 53. The member 50 is preferablysupported on the shaft 5| by a screw 64, the end of which is received ina cylindrical groove 55 formed on the shaft 5|.

The lower end of the cylindrical member 50 is provided with a. recess 56in which is received a laminated armature`51 provided at its ends withpole pieces 58, one of which is indicated in Fig. 2. The armature ispreferably secured in posi tion by a pin 59 fastened to the cylindricalmember 50 and the armature 51. A hub 60 is provided with a flange 6|which is secured to the lower end of the cylindrical` member 50 as byscrews 62.` The hub 60 is providedwith an opening 63 in which isreceived a shaft 64 whichIis.

secured to a transverse shield-32a by a ange 32h the rotation of theparts in the upper portion ofl the casing. On the shaft 84 is mounted asleeve f v65 the lower end of which is interiorly threaded,

as indicated in Fig. 3, and in which isreceive'd a '-tip66 tapering to apoint 61. A v The lower end of the shaft 64 is provided with a tappedopening 68 in which is received `a screw The en d of the arm 39 ispivotally the shaft. The point 69 may be positioned over a point on thechart indicating the position o f a transmitting station. The pointerarm 10 is received in an opening 1| in the tip 68 and rmay be secured inposition by a screw 12. Ay spool 13-is provided with a coil 14 and issecured by clamps 15 to the armature 51. The armature 51 is alsoprovided with pole pieces 16, which extendl downwardly within the cil14.

The terminals of the loop I0 are connected aS Aby leads 10a and'l0b tocollector rings 18 which are connected by. brushes 19 to conductors 80and 8|, respectively, which are in turn connected to receivers 82 and82| which'receive' currents of different characteristicsfrom differenttransmitting stations.

Preferably waves of different lengths are transmitted from theydifferent stations andthe receivers 82 andf82| are tuned to the wavelengths from the respective stations which are received' on the inputside rof the receivers and amplied.

nal so that as that signal increases, the current in the relaycircuit iscorrespondingly increased f and vice versa.r It is to be understood,however,

that waves ofthe same length may be trans'- mitted from differentstations with different mod'- ulated frequencies and the differentmodulated' frequencies yseparated in the audio side rof the receiver.

The armature of the relay 85 is connected to a movable contact member`81 which 'engages' a fixed contact 88, the'contacts being normally heldopen by 'thel relay magnet against. the' action of aspring 89.rThecontacts .81 'and k88 are includedl in a circuit includingconductors and Y9| and a battery 93 which conductors are connected toslip rings 92 mounted on but insulated from the cylindrical member 50 inthe casing 32. 'I'he conductors 90 and 9| within the casing 32 aresupported by an arm 94 mounted on a bracket 95 secured on the bracketmember 35. Conductors v(not illustrated) lead from the slip rings 92 tothe coil 14.

The casing 32 is located in front of the 'chart 44 over which thepointer arm 10 is moved. A

-similar pointe;` .arm 10| is also moved over the It twill be understoodthat the resultant current imypulses vary in proportion to the incomingsig- The end ofthe shaft 64| projects through an opening in the chart44. After the end of the shaft is inserted through the opening in thechart, the' cap 96 is secured in position on the end of the shaft bymeans of a ball 91 which is pressed inv silicon steel or the like whichis quickly magnetized land quickly loses its magnetism is secured on thesleeve 65 and is provided with pole pieces |03 and |03a which cooperatevwith the poles 58 and 16. respectively, of the armature 51. Twopositions are selected. on the chart 44 corresponding to the positionsoccupied by the two transmitting stations located on the surface of theearth. At the one station onthe chart a perforation is made through thechart and throu'gh the frame on which it is mounted, and y the end ofthe shaft.64| -projects.therethrough,' the pointer arm 10|,being'received in the opening of-maximum intensity is induced intheloop and when the coil is in the line of the magnetic waves nocurrent is induced therein. In the embodiment of .my inventionillustrated, the device operates on the minimum current or no currentwithin the loop. In other words, the relay 85, which it will beunderstood should be quick and sensitive, normally maintains thevcircuit comprising the conductors 90 and 9| open and when the antennaloop arrives at the position where no current or the minimumv current isinduced in the loop 0, the relay 85 is de-energized and the circuitcontrolled thereby is closed and the magnetic coil 14 4is energized. Thecap 98 on the shaft 84| and the tip B8 thus constitute oscillatabledevices -located over points on the chart corresponding in position tothe positions of the transmitting stations on the 'surface of the earthand are actuated by the oscillatable members |02.

The rotation of the shaft |2 and the bevel gear |1produces rotation ofthev shaft I9 at the same speed and in the opposite direction throughthe planetary gear 22. The bevel gear 24 rotates the bevel gear 25 andthe bevel gear 28 meshing therewith in the same direction as the bevelgear looking down upon the gears 24,25'and 28 and "points foreachstation when no current or a` 24, and at thesame speed since the twogears have the same 'number of teeth. That is to say,

assuming that the bevel gear 24 rotates clockwise, then .the bevel: gear28 also rotates clockwise in the same direction and at the same speed.The shaft 3| rotates the-bevel gear 46 which in turn rotates the bevelgea;-` 49 at the same speed and this in turn rotates the 'cylindricalmember 50 and the armature 51 mounted thereon at the same speed andinthe same direction as the.

shaft |2.and the loop |0 mounted thereon For each .rotation of the loop|'0 there are two minimum current is induced therein, and Ythe circuitincluding the battery 93 which is 'controlled lthereby is closed twiceand the magnetic coil 14 is twice energized. This minimum lcurrent inthe loop I0 occurs at variable points lin the angular position thereofdependingupon the position ofthe movable-body relative to thetransmitting station and always at the instant that the plane of theloop is at right angles to theline from the movable body tothe giventransmitting station. When the coil 14 is enerund. the laminated mme 51is magnenzed and the poles |03 and |03'a of the part |02 are attractedby the poles 58 and 16 respectively of the armature |51.l Th'e part |02,therefore, is

maintained immediately in front of the arma-` ture` 51, and turns thesleeve on which itis mounted and correspondingly the arm 10 which ismounted thereon so that the direction of the arm 10 which passesVthrough the point on the map which indicates the position of one of thetransmitting stations, corresponds in directionV to the direction of themovable bodyfrom the transmitting station. -Similarly the arm 10| whichpasses through the point on the map which indicates the position ofanother transmitting station,'is maintained in the same direction withreference to the chart that the movable body occupies with reference totheother transmitting station, and the point of intersection of the arms10 and 10| indicates the position of the movable body on the chart 44.

It will be noted that the double bevel gear 25 rotates the bevel gear28| which engages the opposite side thereof from the bevel'gear 2,8 inthe direction opposite to the rotation of bevel gear -28 which iscorrect,` since the casing containing the bearing 32| is yturned (beingonl the opposite side of the map) in the direction opposite to thecasing 32. i

Referring to Fig. l, assume that B on the map which is the point ofintersection of the arms 10 and 10| indicates the position of themovable body. Also assume that the movable body is to move to a positionrepresented bythe point C on the map which is directly south of theposition B. The map indicates that the transmitting staltion at 32 iseasterlyof both of the points B and the bevel gear 25, clockwisemovement of bevel gears 28 and 46 and a counterclockwise movement ofbevel gear 49 and the arm 10. Likewise, the direction from thev point Con the chart to the station 32| indicates that a clockwise directionofthe active position of the loop must now be made. Assuming that theloop is turned clockwise, then the bevel gear I1 is turned clockwise,the bevel gears I8 and 26 counterclockwise and the gear 25, 28| and 46clockwise and bevel-gear v49 counterclockwise which produces a clockwisemovement'of the arm 10| as viewed from the front of the map.

In orderl more easily to `describe and understand the operation of thedevice, let us assume that the loop is' not rotating and that itis movedmanually until the direction of the station is found. lThen therelay-.85 closes the circuit which energizes the coil 14 and therebyholds the arm -10 in a certain position relatively tosaid loop. .In casethe vessel turns clockwise, we have to turn the loop counterclockwisethrough the same-angular` amount to nd the station.- l loop relative torthe ship would also cause the This counterclockwise 'motion of the;

arm 10 to turn 90? counterclockwise, and thus render thejindicationgiven by the pointer inaccurate. The same inaccuracy would of course,I

angle to the photo electric cells.

be present when the antenna loop and associated parts are rotated.

My invention comprises a device indicated gen- I erally at A forcompensating for turning movements of the movable body andovercoming'the inaccuracy that would otherwisev be produced.

In the embodiment of my invention illustrated a rotatable member in theform of a gear |04 is mounted on a shaft |05 having its bearings inframes |3 and |3b which are fixed on and move with the vessel, and thisgear is oriented in a predetermined direction by a device indicatedgenerally at A which will now be described; On the upper end of theshaft |05 ismounted a dished member |06 (see Fig. 9). Amagnetic needle|01 is mounted on a spindle |08 which has its bearings at |09 and ||0 inthe bottom and top plates, respectively, of a casing which is mountedfor universal movement within the dished member |06, the casing beingpivotally mounted in a gimbal ring ||2 which is in-turn rotatablymounted within the dished memberV |06 as in the usual gimbal. Thevmagnetic needle is thuskept in a horizontal positionirrespec- -tive ofAthe movements of the vessel or other movable body o n which the partsshown in Fig. 9 are mounted.

A source of light', which is shown in the form of an incandescent lamp||3 is mounted in an open bottomed casing ||4, the -casing beingVmounted von a standard ||5 which is in turn mounted on the casing Thelamp is included in a circuit -(s ee Fig. 12) in which is included abattery ||6 or other source of electric energy. A transverse opaque`partition ||1 is mounted in the casing ||4 and is provided with anarrow slit ||1a, vas best shown in Fig. 1l,

through which passes a beam or line of jlight.

which then passes through a projecting lens ||8.

thereto. Selenium cells or other-'photo electric cells and I20 a aremounted on the casing and preferably in parallel relation, as best shownin Figs. 1'0 and 12. ends of the cells are mounted two pairs of mirrors|2| and |2|a which are arranged at an The ends vof the two pairs ofmirrors |2| and |2`|a are slightly spaced. The lens ||8 is so locatedrelatively to the slit ||1a in the partition ||1 as normally v toproject the image of the slitthrough the space between the mirrors |2|,

The means for maintaining the gear 04 o ented in a predetermineddirection also comprises a motor indicated generally at |22 which, itwill be understood, is mounted on a stationary portion of the vessel orother movable body. The shaft |23 of .the motor is provided with a worm|24 engaging a wormwheel |25 mounted on the lower end of the shaft |05.Y Y

Referring particularly to Fig. 12\the selenium cells 20 and |20a areconnected by'a conductor |26 to one pole of a battery |21. The'otherpole of the battery is connected tov a point from which the circuitbranches, one portion of the circuit includes a coil |28 andv vconductor|29'which is A mirror ||9 is mounted on the upper end of the spindle |08and preferably at an angle of 45` At the respective Y two windings vmaand mb. The tenmnal or the winding |33a is connected to a movablecontact-|34 which cooperates with aV ilxed'contact |35 whilethe terminalof the eld coil |33b is connectedto a. movable contact |36 cooperatingwith a xedcontact |31, both of the xed contacts |35 and |31 beingconnected by a conductor |38 to the battery |21.- I have illustrated thecoils |28 and |30 surrounding a bar of iron in a direction to produce anorth pole' at the as'- sociated end of the bar when either of saidcoils is energized. A permanent magnet |40 is preierably associated withthe bar |39' so that the v associated end of the bar is depressed whenthe coil |28 or |30 isenergized, and'the contact |34 or the contact |36brought into engagement with the contact |35 or the contact |31, the twocoilsA |28' and |30 being wound 'on the bar |39 in such a direction asto reverse the poles at the vends of the bar |39 when the respectivecoils are energized. The gear wheel" |04 engages an intermediate gear|4| mounted on a shaft |42, the gear I4| in turnengaging the gear Wheel2|.

IThe operationof the device for maintaining.

the spindle thereof will remain stationary. The

beam oi light 45 then instead of passing through the opening between themirrors |2| will be directed against one or the other of the photoelectric cells. depending upon the direction of turn.- ing of thevessel. Assuming that,t he vessel so 'turns that the light ts directedagainst the sele.

nium cell |20, then the resistance o! the cell is greatly. decreased andthe coil |28 which is included in the circuitof'that cen and whichnormally de-energized is now energized and theassociated end of the bar|39 is attracted by the magnet. and the left hand end of the bar, aslviewed in Fig. 10 brings the movable contact |34 into engagement withthe stationary contact |35 thereby closing. a circuit -from the battery|21 through the armature of the motor, the field coil 33a and thecontacts 34 and |35 to th other pole of the battery |31. The armatureofthe motor is thereby rotated in a direction to cause the dished memberto turn in a direction to bring the mirrors |2| and |2 |a back to theposition where the' light beam from the mirror ||9 passes through theopening between the mirrors |2|. The shai't |05 is thereby rotated -bythe motor sulciently to bring the v,gear |04 to its normal orientedposition. Conversely, should the vessel turn in the opposite direction,then'the light from the lamp ||3 would be directed against the photoelectric cells |20a, the contacts |36 and |31 would be closed and 'thecircuit closed'through the armature of the motor and through the field|3311, and as the current is'thereby reversed in the eld, the armatureof the motor would then rotate in the opposite direction therebyreturning the photo electric cells and the gear |04 to their normalpositions.

As thevgear 04 is maintained in a predetermined orinted position; theintermediate gear |.4| is rotated, during the turning .movement of v thevessel, and the gear wheel 2| 'is correspondingly rotated. The gearratio of the gear 2| to that of the gear |04 is two to one so thatshould the vessel turn through an angle of 90, the gear wheel 2| Iwouldturn through an angle of 45. Such movement of the gear wheel 2| producesa planetary movement vof the gear 22, and, assuming that the bevel gear|8 of the differential4 the same angle that the vessel has turned. This.vmovement of the gears comprising the differential gear turns the loop|0 relatively to the indicating mechanism and thereby compensates forany turning of the vessel in a horizontal directionl which wouldotherwise preclude proper readings 85 which in turn controls a circuitincluding conductors 90and 9| and a battery 93 in a manner also similarto the arrangement illustrated in,

Fig. 1.

Bevel gear 46 is mounted within a casing the same or similar to thecasing 32 Iand is driven by |53 and the hub |50 of the gear |49 may bethe shaft 3| (not illustrated). The bevel gear 46 engages a bevel gear49 mounted on a shaft |43` having a bearing in a sleeve |44 in an arm38a which is movable in a manner similar to the arm 38 illustrated inFig. 1 on which thecasing 32 is mounted. A disc |45 formed of insulatingmaterial is secured to the shaft |43 and is provided with a slip ring|46' which is engaged by a contact member |41 which is presseddownwardly by a spring |48 as best shown in Fig. 13. The conductor 9| isconnected to the contact member |41. The shaft is surrounded by a gear|49 formed of fiber or other insulating material which is provided with-a hub. |50 surrounding a bearing sleeve |5| the lower end of whicnisprovided with an Opening |52 in which secured to the sleeve |5| by ascrew |54 which engages a groove ,-formed in the shaft |43 and whichprevents relative longitudinal movement between the shaft and the sleeve|5| and hub |50. Two continuous slip rings |56 and |51 are embedded inthe upper surface of the disc |49 which is adapted to coact with and -bemoved byv pawls |84 and |84a which -will hereinafter. ybe more fullydescribed. Sleeve |68 is supported on shaft |66 which extends through anopening |61 of arm 38a the head |10 thereof bearing against 5 the uppersurface of arm 38a, the sleeve |68 being retained in position on theshaft |66 by-a removable head |1| adapted to be secured on the lower endof the shaft |66 as `by a pin |12. One of the conductors 9| of thecircuit in which is the battery 93 is connected to the contact member|41 engaging the collector ring |46 and the other conductor 90 isconnected through coils |13 and |14 to the contact members |63 and |64respectively. The coils |13 and |14 are mounted in a 15 U-shapedpermanent magnet |15 provided with pole pieces |16 and |11. The coils|13 and |14 surround an armature |18 secured to ashaft |19 having itsupper bearing at |80 in a bracket |8| secured to the bracket arm 38a asbest shown inv 20 Fig. 13 and having its lower bearing at |82 in abearing on the' permanent magnet |15. A T-shaped member |83 is securedto the'shaft |19 and is provided at the ends of the cross arm of the Twith pawls |84 and'l84a, the ends of which '25 are directed toward eachother and engage the ratchet wheel 69. If, at the time when the mini-`mum signal is received in the antenna loop |0,

and the circuit including the conductors 90 and 9| isA closed, thelindicator arm 10 points in the 30 proper direction, ythe contact memberwill be located over an insulating member |59 and the circuit includingthe conductors 90 and 9| will be open.

If, on' the other hand, the indicating arm 10 35 does not correspond' inposition to the direction of the movable body from the transmittingstation, then when the minimum signal is received in the antenna loop l0and themovable contact member 81 is brought into engagement with the 40fixed contact member 88, the contact member |60 will engage-either thesegmental contact |58a or |58b, depending upon the direction that theindicator arm is dislocated from its correct position. Assuming that thecontact |60 engages 45 the segmental contact |58a then a circuit isclosed from the battery 93 through the contact members 81, 88, coil |13,contact |63, segmental contact |58a., contact. |60 and slip ring |46,contact member |41 to the other side of the battery 93. 50` The armature|18 will be attracted towards thev pole piece |11 and the pawl |84a.will move the ratchet wheel |69 through an angle represented by onetooth. It will be understood that the pawls I pawl is y:freedtherefrom.v The pawls then assume their /normalV position and -if on thenext half and an' inner ring |58 is interrupted by insulat"\rotation ofthe antenna loop I0, the contact mem two diametrically opposite segments|58a of thev I' ringbei-ng electrically connected to the outer slip ring|56 while the other two diametrically opposite segments |58b areelectrically connected to the inner slip ring |51. Acontact memberI|.60`engages the ring I581and is provided with a stem |6| received inasleeve |62 which is -mounted in an opening in the disc and which is,

electricallyl connected to the slip ring |46. The collector rings' |56and |51 areengaged by contacts |63 and |64v mounted on the arm 38a.. Avpinion |65, adapted to mesh withy the teethofgear |49', is mounted on. asleeve |68 'and prefer.. ably integral therewith. The sleeve |68 isprovided at its lower'` end with a ratchet wheel les ber |60 stillengages the segmentalcontact |58a, 30

Y the coil| 13 will again be energized and the ratchet moved throughvanother tooth. This-cycle `will be repeated until the contact member|60 is again brought into engagement with the insulating "member'I59 .atthe instant that the minimum 55 signal is receivedin the antenna loop.

If, yon the other hand, the contact member |60 is located over thesegment |5811 when a .minimum signalisrcceived in the antenna loop, thenthe :2011114 is energized and the ratchet wheel |69 will be. rotated inthe opposite. direction to return the'indicator hand 10 towards itscorrect position. v

In. Fig. 15 I have illustrated a sensitive relay which is better adaptedto respond to the rather feeble currents from the receiver thanthatillustrated in Fig. 5. In the embodiment here illustrated the outputside of the receiver 82 is connected to the primary 82| of a:transformer the secondary 822 of which is connected to the coil (notillustrated) of a galvanometer |85 through a permanently adjustedcrystal 823 or other suitable type of valve. This arrangement gives thegalvanometer pulsating direct current and holds the mirror to one sideonly and is also free from current when no signal is received; Thegalvanometer is provided with the usual oscillatable member |86 actuatedbythe coil (not illustrated) and on which is mounted a mirror |81. eAsource of light, illustrated as an incandescent lampV |88, included in acircuitv comprising a battery |89, projects a beam of light througha-slit |90 ina shield |9| and through a lens |92 against the mirror |81vfrom which it is `reected.- VA light shield |93 is so arranged withreference to the associated parts that the beam of light from the lamp|88 is directed against the shield 93 except when the minimum signal isreceived in the antenna loop I0 at which time the beam of light from thelamp is reflected past the edge ofthe shield |93 against the seleniumcell |20. The circuit including the selenium.cel1 |20 and whichcorresponds to the circuit including the conductors 90- and 9| in Figs.1 and 14 is thereby closed.

In` Fig. 16, I have illustrated a device in which my invention is usedfor recording on a chart the course pursued by a movable body.- A chart4'4 is mounted on a suitable frame and arms 10 and 10| move over thechartas in Fig. 1. Slidable sleeves |94 and |94a are tted over the armsand the arms are slidable therethrough. The two sleeves |94 and |94a arepivoted together, preferably by a sleeve |95 through whichextends arecording stylus |96 connecting with a suitable receptacle |91, thestylus being lightly forced against the chart by a tension spring |98attached to the sleeve |94 and to a stem |99 secured to the head 208 onthe stylus |98. When thetwo members 32 and 32| are located over pointson the chart which indicate the positions or the stations from whichsignals are transmitted then the intersecting point of the two arms '|28and 12| always indicate on the chart the position of the movable body.By providing a slidable mem.- ber and a recording device attachedthereto, such device will follow on the chart the course pursued by themovable body and the recording means will produce on Ithe chart a lineindicating the course pursued by the, vessel or other movable While Ihave illustrated intersecting arms for indicating on a chart theposition of a movable body, it will be understood that intersectinglines of light produced in the manner illustrated in my application Ser.No. 646,728'Which was led in the Patent Oflce on or about December 10,1932 may be used in place of the arms. A y

In either case, visible linear intersecting indicators are produced oversaid chart which are maintained in positions with respect to said chartcorresponding to the directions of said body from the respectivetransmitting stations. It will also be understood that two directioniinders of the character illustrated in my application Ser. No. 646,730which was illed in the PatentOfceon or about December 10, 1932 may b'eused for controlling the intersecting line which moves over the chartinstead of the single rotatable direction nder illustrated herein.

Under some conditions as where a coast line is known or is visible asingle linear indicator may be sumcient for coast navigation and thelinear indicator crosses the line indicating the coast.

While I have illustrated photoelectric cells and associated means formaintaining the gear wheel |04 oriented in a predetermined direction.

it will be understood that any known means may beutilized for thispurpose.

While I have described my invention in its preferred embodiment, it isto be understood that the words which I have used are words ofdescription and not of limitation and that. changes Within the purviewrof the appended claims may be made without departing from the true scopeand spirit of my invention in its broader aspects. What I claim is:

1. In a navigating apparatus for a movable body, a rotatable antennaloop tuned to receive electromagnetic waves transmitted from a pluralityof spaced stations, a chart mounted upon said body, a plurality ofintersecting linear in dicators movable over said chart, a plurality ofrotatable members, means for rotating said loop and said memberssubstantially in synchronism, means responsive to a turning movement ofsaid body for producing the same relative angular movement between saidloop and said rotatable members, and means comprising said loop andsaidv members for maintaining said indicators in directions with respectto said chart corresponding to the directions of said body from therespective stations.

2, In a navigating apparatus for a movable body, a rotatable antennaloop tuned to receive electromagnetic waves transmitted from a pluralityof spacedstations, a chart mounted upon and fixed with respect to saidbody, a, plurality of intersecting linear indicators movable oversaidchart, a plurality of rotatable members. means for rotating said loopand saidmembers substantially 4in synchronism, means responsive to aturning movement of said body for producing the same relative angularmovement between said loop and said rotatable members, and meanscomprising said loop and said members for maintaining said indicator indirections with respect to said chart corresponding to the directions ofsaid body from the respective stations.

3. In a navigating apparatus for a movable body, a 'chart mounted onsaid body and fixed with respect thereto, means for receivingelectromagnetic waves transmitted from known stations, means controlledby -said receiving means and movable relative to said chart whereby saidmeans may be positioned over points on said chart representing thegeographical location of Said stations, said last mentioned meanscomprising meansl for indicating on said chart the position of saidmovable body, and means operable in response to a turning movement ofsaid body for correcting the eiect of such movement on the 5. In anavigating apparatus for a movable body, a chart mounted on said bodyand xed with respect thereto, means'for receiving electromagnetic wavestransmitted from distant sta-- tions, means for indicating on said chartthe position of said movablebody, electrical means controlled by saidreceiving means for actuating said indicating means, and means operablein response to a turning movement of said body for correcting the eiectof such movement on said indicating means.

6. In a navigating apparatus for a movable bodyfa chart mounted on saidbody and xed with respect-thereto, means for receiving electromagneticwaves transmitted om known stations, means comprising p'ivotallymounted, linear indicators, said last mentioned means being movingmeans.

7. In a device of the cha acter described for use on a movable body, achart'mounted on said body and xed with respectthereto, means forreceiving electromagnetic waves transmitted from distant stations, meanscomprising a pivotallv mounted, linear indicator adapted to extend oversaid chart and movable relative thereto whereby said indicator may bepositioned to pivot over Ypoints on said chart representnig thegeographical location of said stations, means controlled by saidreceiving means for actuating said indicator and means-operable inresponse to a turning movementof s aid bodyfor correcting the effect ofsuch movement on the position of said indicator over said chartf- 8.In-a device of the character described for use on a movable body,receiving means comprising arotatable loop antenna and meanselectrically connected with said loop .for tuning to desiredelectromagnetic waves, means comprising a pivotally mounted,linear indicator. and electrical 9. In a device of the characterdescribed forv use on a movable body, receiving means comprising a'rotatable loop antenna and means elecfurther controlling saidelectricalmeans for pomcauy connected with ma loopror tuning te desiredelectromagnetic waves, means comprising able in response to a turningmovement of said body forv effecting an asynchronous rotation of saidantenna and indicator control-means where- 10 by the effect of suchmovementon said indicator is compensated for.

10. In a device of the 'character described for use on a movable body,means for receiving electromagnetic waves transmitted from distant sta-15 tions comprising a loop antenna. a pivotally mounted, linearindicator, means for controlling said indicator, means including anepicyclic gear train for rotating said antennaand'last-men- 'tionedmeans substantially in synchronism, and 20 means operable in response toa turning movement of said body for effecting an asynchronous rotation'of said loop and indicator control means whereby the eiect of saidturning movement on said indicator is remedied. ,v

11. In a device of the characterdescribed for use on a movable body,receiving means compneing a rotatable loop antenna and meanseiectricallyconnected with said loop for tuning to desired electromagnetic waves,means comprising a pivotally mounted, linear indicator and rotatablymounted, electromagnetic means controlled by' said receiving means foractuating said indicator,

means Vfor rotating said loop and last-mentioned' means substantially insynchronism and means I operable in response to a turning movement of.said body for effecting an asynchronous rotation of said antenna andelectromagnetic means wherebythe eilect or such'movement on saidindicator is compensated for.-

12. In a navigating .apparatus for a movable body, a chart mounted onsaid body and ilxed with respect thereto, means for receivingelectromagnetic waves transmitted from distant stations, means forindicating on said chart the position of said movable body, electricalmeans controlled by said receiving means .for positioning saidindicating means, and means operable in respense to a. turningmovementxofrsaid body for 5o sitioning the indicating means whereby theeitect of such turning movement of said body on said electricalpositioningmeans is compensated'tor.

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